Meniscus Injuries Part 2 - Diagnosis & Acute Stage
In Part 2, we will discuss some key factors that must be considered when performing a physical examination, including the role played by imaging. We will also cover the initial phases of treatment after a meniscus injury has occurred.
START WITH A THOROUGH PHYSICAL EXAMINATION
With any suspected case of meniscus injury, it is critical to perform a complete physical examination.
Physical examinations must include a thorough history, orthopedic testing and a neurological examination.
Diagnostic imaging may also be a critical component when determining the degree of meniscus injury.
EXAMINATION FINDINGS THAT INDICATE MENISCUS INJURY
The following are common examination findings that could indicate the presence of a meniscus injury:
Joint Effusion (increased intra-articular fluid): Caused by an increased level of fluids in the synovial cavity of the knee joint. Joint effusion could also indicate problems with the cruciate ligaments, or the articular cartilage.
Joint Line Tenderness: This is tenderness in the space (line) directly between the femur and tibia. This line runs horizontally on both sides of the knee from the front to the back. Research has demonstrated very high sensitivity and specificity in the diagnosis of both medial and lateral meniscus tears. (7)
Medial meniscus derangement: sensitivity of 76.2% and specificity of 82.5%.
Lateral meniscus derangement: sensitivity of 68.4% and specificity of 96.9%.
Quadriceps Atrophy: The quadriceps muscle often starts to shut down shortly after a meniscus injury occurs. Considerable atrophy of the quadriceps is often noticed within one or two weeks after the injury.
Expect Decreased AROM: The following numbers represent the normal ranges-of-motion.
Knee Flexion: 0 to135 degrees.
Knee Extension: 0 to 15 degrees.
Medial Rotation of Tibia on the Femur: 20 to 30 degrees.
Lateral Rotation of Tibia on the Femur: 30 to 40 degrees.
See this link for anatomical terminology.
McMurray’s Test: This test is performed with the patient lying on their back, while the examiner flexes the patient’s knee. A positive finding of a suspected meniscus tear occurs when a click or snapping is felt at the joint line as the knee is brought from full flexion to 90 degrees of flexion. (7) (Video of McMurray's Test)
Medial meniscus derangement: sensitivity of 48% and specificity of 94%.
Lateral meniscus derangement: sensitivity of 65% and specificity of 86%
Thessaly Test at 5 and 20 degrees: This test is performed at 5° and then 20° of knee flexion. The examiner supports the patient by holding their outstretched hands. The patient stands flatfooted on the floor. The patient then rotates their knee and body, internally and externally, three times, keeping the knee in slight flexion (5°). The same procedure is then carried out with the knee flexed at 20°. (7) (Video of Thessaly Test)
5 Degree Test -Lateral meniscus derangement: sensitivity of 81% and specificity of 91%
20 Degree Test - Medial meniscus derangement: sensitivity of 89% and specificity of 97%.
20 Degree Test - Lateral meniscus derangement: sensitivity of 92% and specificity of 96%.
Other Orthopedic Tests
You can also use the following orthopedic tests, as required:
MAGNETIC RESONANCE IMAGING - MRI
Magnetic Resonance Imaging provides some of the best imaging results. MRI provides an accuracy of 88% for medial meniscal tears and 92% for lateral meniscal tears. (3)
Interestingly, the accuracy of these results are very similar to the accuracy of results derived through a comprehensive physical examination. In other words, research is showing that a comprehensive physical examination is an equally valuable diagnostic tool, and should be integrated into the information derived from imaging.(3)
This is not to say that an MRI should not be performed, but it should not be the first procedure conducted, especially considering MRI costs, and the fact that equivalent information that can be obtained from a thorough physical examination. (3)
Clinical Tip: Even though X-rays are not of high value in diagnosing meniscus injuries, X-rays should still be taken. X-rays provide other valuable information that can aid in ruling out degenerative joint changes, fractures, or pathological processes. The recommended views are an anteroposterior weight-bearing view, posteroanterior 45º flexed view, lateral view, and Merchant Patellar view.
TYPES OF MENISCUS TEARS
There are 3 basic shapes of meniscal tears: longitudinal, horizontal and radial.
Complex tears are a mixture of these basic three shapes.
When we speak of a “bucket handle tear” we are talking about a longitudinal tear that has been displaced.
A “flap tear” is a horizontal tear that has been displaced.
And a “parrot beak tear” is a radial tear that has been displaced. (4)
One of the most common cause of a locked knee is a bucket-handle meniscus tear.
WHAT SHOULD YOU DO WHEN A MENISCUS INJURY HAS OCCURRED?
First off, seek immediate medical attention if you show any indications of a meniscus tear. It is extremely important to determine the severity of the meniscus injury.
The severity of your injury will determine the type of strategy that must be implemented to address your meniscus tear. It is also important to stop all further activities that may cause further damage to the knee until a practitioner has completed their assessment.
Upon initial of the Meniscus injury
No matter what the severity of the injury is - at the initial onset of a meniscus tear, follow the RICE (rest, ice, compression, and elevation) procedure.
Rest - Avoid putting excess stress on the knee. If necessary, use crutches, and a neoprene brace to keep the knee locked in extension.
Ice – Apply ice to the knee for 20-30 minutes, every 2-3 hours, until the swelling is reduced.
Compression - An elastic tensor bandage on your knee may also help to reduce swelling and can be used in conjunction with the ice.
Elevation - Elevating your knee helps to reduce swelling. Place your knee on a blanket or pillow.
Let’s Define What We Mean by Rest
Depending on the severity of the injury, in order to fully recover, it may be necessary to rest your knee completely for several weeks. Initially, you should avoid any activities that involve flexion of the knee. The act of flexing your knee creates tension in the popliteus and semimembranosus muscles. These structures connect into the meniscus, resulting in increased stress in this area.
Clinical Tip: Keeping the injured knee in a locked position, in full extension, will take about 50% of the compressive load off the knee.
Resting the injured leg does NOT mean avoiding all physical activity.
Exercising the lower extremity of the non-injured leg will help to maintain overall muscle mass on the injured leg.
By exercising the opposite leg, there will be some neurological crossover, which helps keep the muscles on the injured side from atrophying.
Electrical stimulation, such as inferential current, can also aid in preventing muscle atrophy of the injured leg, and do so without causing additional stress on the meniscus.
CONCLUSION PART 2
Performing a thorough physical examination is critical for any suspected cases of meniscus injury. Some of the possible examination finding are:
Increased joint effusion.
Increased joint line tenderness.
Decreased active range-of-motion (AROM).
Positive McMurray’s Test.
Positive Thessaly’s Test.
Research shows that MRI imaging is one of the best way to gather information for determining the degree and type of meniscus injury. But a thorough medical and physical examination can provide equivalent results.
There are 3 basic shapes of meniscal tears: longitudinal, horizontal and radial.
If meniscus injury is suspected, seek medical attention immediately.
No matter what the severity of the injury is, at the initial onset of a meniscus tear, follow the RICE (rest, ice, compression, and elevation) procedure.
In Part 3 of Meniscus Injuries (the conclusion) we will discuss how to use Manual Therapy, Exercise, and Surgical Solutions to effectively address Meniscus Injuries.
Note: References for "Knee Pain - Meniscus Injuries "are at the end of Part 3.
DR. BRIAN ABELSON DC.
Dr. Abelson believes in running an Evidence Based Practice (EBP). EBP's strive to adhere to the best research evidence available, while combining their clinical expertise with the specific values of each patient.
Dr. Abelson is the developer of Motion Specific Release (MSR) Treatment System. His clinical practice in is located in Calgary, Alberta (Kinetic Health). He has recently authored his 10th publications which will be available later this year.
Dr. Abelson is the owner of Kinetic Health, a partner in BKAT Motion Specific Release, and a partner in Rowan Tree Books.